Read your report once more knowing that you are composing an abstract. Keep in mind your purpose, scope, results, methods, conclusions and recommendations.
Sketch out a rough draft of an abstract without looking at your report. You will offer either too much information or not enough in the abstract if you copy sentences directly from your report. Instead, only think about the primary points in the main parts of your report.
Communicate your report's contents in your abstract. Use one or more paragraphs that present an introduction, body and conclusion. An abstract should be 10% or less of your report's length.
Include short sections within your abstract paragraphs -- even if only a sentence each -- that present your problem statement, motivation, approach, results and conclusions. One section addresses the problem you are solving, including the scope of your work. In your motivation section, show the reader the importance of your work, its difficulty, why he should care about the problem and the impact of the results. Your approach section presents the progression of your problem solving. Write your solution in a results section. Conclude with a section offering implications of your results.
Follow the chronology of your report to show the reader logical links between the information you offer. For example, if you present your report in sections (problem statement, motivation and approach), follow the same order in your abstract.
Structure your abstract so that it can stand alone and makes sense by itself. Do not be vague, because your abstract represents a totally self-contained description of your paper. Databases online usually only contain abstracts for reports. Complete, succinct descriptive abstracts thus encourage readers to pursue entire reports.
Think about keywords and search phrases readers searching for your report might employ. Use those phrases in your abstract in order for those exact terms to show up at the top of a search listing.
Revise, edit and tweak your rough draft to assure organization and unity. Check to make sure you do not leave out significant data, and omit anything irrelevant. Do not add any information that is not in your report. Revise any section or sentence that is too wordy.